Major cell types of the lung are being isolated and studied for their metabolisms of xenobiotics and selected lipids (in comparison with liver cells). Special studies are being made with Clara, type II and ciliated cells of the lung. Studies of the effects of the techniques used in isolating the enriched populations of cells from tissues are being made with various antibodies to selected cytochrome P-450 isozymes and Western blotting/microdots for quantifying these isozymes and related peptides in cells at various stages in the isolation procedures. A microspectrophotofluorometer is being used to quantify xenobiotic metabolism in single cells and to study variations in this metabolism among cells of an "homogenous" population. Variations in enzyme activity in periportal and centrolobular liver cells in the perinatal period are compared with these activities in the adult liver. Lung cells from dogs and humans are being prepared and analyzed for P-450 isozymes and xenobiotic metabolism in comparison with cells from the rabbit.